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dyarosh
 asked on

Using an ASP.NET User Control

I am new to creating custom web controls and wanted to start with something simple so I am trying to create a DropDown List for State to be used on address forms.

I am able to set the initial value but when I change the value and try to retrieve it, I am getting the original value that the control was initialized to.

Here is my code for the control (StateUserControl.ascx)
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="StateUserControl.ascx.cs" Inherits="CVL.StateUserControl" %>
<asp:DropDownList ID="StateDropDownList" ClientIDMode="Static" runat="server">
    <asp:ListItem Value=""></asp:ListItem>
    <asp:ListItem Value="AL">Alabama</asp:ListItem>
    <asp:ListItem Value="AK">Alaska</asp:ListItem>
    <asp:ListItem Value="AZ">Arizona</asp:ListItem>
    <asp:ListItem value="AR">Arkansas</asp:ListItem>
    <asp:ListItem value="CA">California</asp:ListItem>
    <asp:ListItem value="CO">Colorado</asp:ListItem>
    <asp:ListItem value="CT">Connecticut</asp:ListItem>
    <asp:ListItem value="DE">Delaware</asp:ListItem>
    <asp:ListItem value="DC">District of Columbia</asp:ListItem>
    <asp:ListItem value="FL">Florida</asp:ListItem>
    <asp:ListItem value="GA">Georgia</asp:ListItem>
    <asp:ListItem value="HI">Hawaii</asp:ListItem>
    <asp:ListItem value="ID">Idaho</asp:ListItem>
    <asp:ListItem value="IL">Illinois</asp:ListItem>
    <asp:ListItem value="IN">Indiana</asp:ListItem>
    <asp:ListItem value="IA">Iowa</asp:ListItem>
    <asp:ListItem value="KS">Kansas</asp:ListItem>
    <asp:ListItem value="KY">Kentucky</asp:ListItem>
    <asp:ListItem value="LA">Louisiana</asp:ListItem>
    <asp:ListItem value="ME">Maine</asp:ListItem>
    <asp:ListItem value="MD">Maryland</asp:ListItem>
    <asp:ListItem value="MA">Massachusetts</asp:ListItem>
    <asp:ListItem value="MI">Michigan</asp:ListItem>
    <asp:ListItem value="MN">Minnesota</asp:ListItem>
    <asp:ListItem value="MS">Mississippi</asp:ListItem>
    <asp:ListItem value="MO">Missouri</asp:ListItem>
    <asp:ListItem value="MT">Montana</asp:ListItem>
    <asp:ListItem value="NE">Nebraska</asp:ListItem>
    <asp:ListItem value="NV">Nevada</asp:ListItem>
    <asp:ListItem value="NH">New Hampshire</asp:ListItem>
    <asp:ListItem value="NJ">New Jersey</asp:ListItem>
    <asp:ListItem value="NM">New Mexico</asp:ListItem>
    <asp:ListItem value="NY">New York</asp:ListItem>
    <asp:ListItem value="NC">North Carolina</asp:ListItem>
    <asp:ListItem value="ND">North Dakota</asp:ListItem>
    <asp:ListItem value="OH">Ohio</asp:ListItem>
    <asp:ListItem value="OK">Oklahoma</asp:ListItem>
    <asp:ListItem value="OR">Oregon</asp:ListItem>
    <asp:ListItem value="PA">Pennsylvania</asp:ListItem>
    <asp:ListItem value="RI">Rhode Island</asp:ListItem>
    <asp:ListItem value="SC">South Carolina</asp:ListItem>
    <asp:ListItem value="SD">South Dakota</asp:ListItem>
    <asp:ListItem value="TN">Tennessee</asp:ListItem>
    <asp:ListItem value="TX">Texas</asp:ListItem>
    <asp:ListItem value="UT">Utah</asp:ListItem>
    <asp:ListItem value="VT">Vermont</asp:ListItem>
    <asp:ListItem value="VA">Virginia</asp:ListItem>
    <asp:ListItem value="WA">Washington</asp:ListItem>
    <asp:ListItem value="WV">West Virginia</asp:ListItem>
    <asp:ListItem value="WI">Wisconsin</asp:ListItem>
    <asp:ListItem value="WY">Wyoming</asp:ListItem>
</asp:DropDownList>

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Here is the code behind on the control:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace CVL
{
    public partial class StateUserControl : System.Web.UI.UserControl
    {
        public string StateName
        {
            get { return StateDropDownList.SelectedValue; }
            set 
            {
                StateDropDownList.ClearSelection();
                StateDropDownList.Items.FindByValue(value).Selected = true;
            }
        }
    }
}

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Here is the code behind on my test page:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace CVL
{
    public partial class Test : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            StateName.StateName = "FL";
        }

        protected void SaveBTN_Click(object sender, EventArgs e)
        {
            StatusLBL.Text = StateName.StateName;
        }
    }
}

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As you can see, I initialize the drop down to FL (Florida).  Florida displays on the screen as expected.

When I select a different state such as Delaware, the screen shows Delaware but when I click on Submit to display the selected value, I get FL.  I am expecting DE.  Can someone tell me what I am doing wrong?
ASP.NET

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Last Comment
dyarosh

8/22/2022 - Mon
dyarosh

ASKER
I've narrowed the problem down to the foloowing code:

StateDropDownList.Items.FindByValue(value).Selected = true

For some reason, this doens't allow me to get a differenct selected value.
Andy Green

The problem is that the user control is distroyed on postback along with any value.

I had a similar problem recently and these links helped.

http://stackoverflow.com/questions/5425679/findcontrol-wont-find-my-dynamically-added-usercontrol


http://www.codeproject.com/Articles/59781/Dynamic-Loading-of-ASP-NET-User-Controls

Andy
Andy Green

This is the original thead I posted, there are some other clues in there too.

http://www.experts-exchange.com/Programming/Languages/.NET/ASP.NET/Q_27968007.html

Andy
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James Murphy
dyarosh

ASKER
Thanks for the links but I am not loading my controls dynamically.  All the controls are placed on the web page and are static.  If I don't try and initialize the value of the DropDownList then everything works fine.  It is only when I try and initialize the value that I run into the problem.
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Andy Green

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dyarosh

ASKER
Thank you.  I didn't even realize I was missing that until you pointed it out.  So dumb!!!